This invention relates generally to door locks having a pin tumbler locking mechanism, and more particularly to changing the pin tumbler combination by use of a replaceable lock core cylinder.
It is often desirable to change the pin tumbler combinations of several locks for a variety of reasons. When such changes are necessary, it is potentially both expensive and time-consuming. In order to minimize these drawbacks, rekeying systems have been developed with varying degrees of desirability. Some require excessive disassembly of the lock mechanism in order to change keying. Others, although relatively easy to replace, compromise security by allowing relatively easy removal by unauthorized persons, because they are susceptible to tampering.
Even without tampering, some replaceable cylinders are subject to inadvertent removal. For example, in locations where the lock mechanism is subject to corrosion or build-up of contaminants, the interface between the key plug and the core cylinder retention mechanism may become tight enough to disengage the retention mechanism and permit removal of the core cylinder with a standard key while merely trying to unlock the lock. This is most likely to happen in the case where the retention device is spring loaded and has become contaminated or worn due to long use, abuse, or tampering. These are well-known disadvantages of the present state of the art.
The foregoing illustrates limitations known to exist in present interchangeable lock core cylinders. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.